RedBalloon (manual link above)
Save the offer to your eligible Card and spend $250 or more, in one or more transactions, online only at www.redballoon.com.au by 27/09/2019 to receive one $50 credit. Limited to the first 20,000 Cards to save the offer. Exclusions apply.
Sydney Trains/Ferries/Light Rail (targeted)
There are different versions of this targeted offer, so far I've seen get 40% back up to $30 and get 30% back up to $15. Expires 24/09/2019.
More info. Thanks forumninja
Wish sydney buses were included